Sex ratio is the ratio of males to females in a population. The primary sex ratio is the ratio at the time of conception, secondary sex ratio is the ratio at time of birth, and tertiary sex ratio is the ratio of mature organisms.^[1]

The human sex ratio is of particular interest to anthropologists and demographers. In humans the secondary sex ratio is commonly assumed to be 105 boys to 100 girls (which sometimes is shortened to "a ratio of 105"). In human societies, however, sex ratios at birth may be considerably skewed by factors such as the age of mother at birth^[2], and by sex-selective abortion and infanticide. The CIA estimates that the current world wide sex ratio at birth is 107 boys to 100 girls.^[3] In 2010, the global sex ratio was 986 females per 1,000 males and trended to reduce to 984 in 2011.^[4]

Sex ratio theory[link]

The theory of sex ratio is a field of study concerned with the accurate prediction of sex ratios in all sexual species, based on a consideration of their natural history. The field continues to be heavily influenced by Eric Charnov's 1982 book, Sex Allocation.^[5] He defines five major questions, both for his book and the field in general (slightly abbreviated here):

1. For a dioecious species, what is the equilibrium sex ratio maintained by natural selection?
2. For a sequential hermaphrodite, what is the equilibrium sex order and time of sex change?
3. For a simultaneous hermaphrodite, what is the equilibrium allocation of resources to male versus female function in each breeding season?
4. Under what conditions are the various states of hermaphroditism or dioecy evolutionarily stable? When is a mixture of sexual types stable?
5. When does selection favour the ability of an individual to alter its allocation to male versus female function, in response to particular environmental or life history situations?

Biological research mostly concerns itself with sex allocation rather than sex ratio, sex allocation denoting the allocation of energy to either sex. Common research themes are the effects of local mate and resource competition (often abbreviated LMC and LRC, respectively).

Fisher's principle[link]

Fisher's principle explains why for most species, the sex ratio is approximately 1:1. Bill Hamilton expounded Fisher's argument in his 1967 paper on "Extraordinary sex ratios"^[6] as follows, given the assumption of equal parental expenditure on offspring of both sexes.

1. Suppose male births are less common than female.
2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring.
3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them.
4. Therefore the genes for male-producing tendencies spread, and male births become more common.
5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away.
6. The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio.

In modern language, the 1:1 ratio is the evolutionarily stable strategy (ESS).^[7]

Types of sex ratio[link]

The sex ratio varies according to the age profile of the population. It is generally divided into four:

• primary sex ratio — ratio at fertilization
• secondary sex ratio — ratio at birth
• tertiary sex ratio — ratio in sexually active organisms
• quaternary sex ratio — ratio in post-reproductive organisms

Measuring these is a problem since there are no clear boundaries between them.

Examples in non-human species[link]

Environmental[link]

Spending equal amounts of resources to produce offspring of either sex is an evolutionarily stable strategy: if the general population deviates from this equilibrium by favoring one sex, one can obtain higher reproductive success with less effort by producing more of the other. For species where the cost of successfully raising one offspring is roughly the same regardless of its sex, this translates to an approximately equal sex ratio.

Bacteria of the genus Wolbachia cause skewed sex ratios in some arthropod species as they kill males. Sex-ratio of adult populations of pelagic copepods is usually skewed towards dominance of females. However, there are differences in adult sex ratios between families: in families in which females require multiple matings to keep producing eggs, sex ratios are less biased (close to 1); in families in which females can produce eggs continuously after only one mating, sex ratios are strongly skewed towards females.^[8]

Several species of reptiles have temperature-dependent sex determination, where incubation temperature of eggs determines the sex of the individual. In the American Alligator, for example, females are hatched from eggs incubated between 27.7° to 30 °C, whereas males are hatched from eggs 32.2–33.8 °C. In this method, however, all eggs in a clutch (20–50) will be of the same gender. In fact, the natural sex ratio of this species is five females to one male.^[9]

Dioecious plants secondary sex ratio and amount of pollen[link]

It was found that the amount of fertilizing pollen can influence secondary sex ratio in dioecious plants. Increase in pollen amount leads to decrease in number of male plants in the progeny. This relationship was confirmed on four plant species from three families – Rumex acetosa (Polygonaceae),^[10][11] Melandrium album (Cariophyllaceae),^[12][13] Cannabis sativa^[14] and Humulus japonicus (Cannabinaceae).^[15]

Individual[link]

In birds, mothers can influence the gender of their chicks. In peafowl, maternal body condition can influence the proportion of daughters in the range from 25% to 87%.^[16]

In several different groups of fish, such as the Wrasses, Parrotfish, Clownfish, dichogamy — or sequential hermaphoditism — is normal. This can cause a discrepancy in the sex ratios as well. In the Bluestreak cleaner wrasse, there is only one male for every group of 6-8 females. If the male fish dies, the strongest female changes its sex to become the male for the group. All of these wrasse are born female, and only become male in this situation. Other species, like clownfish, do this in reverse, where all start out as non-reproductive males, and the largest male becomes a female, with the second-largest male maturing to become reproductive.

Economical[link]

Traditionally, farmers have discovered that the most economically efficient community of animals will have a large number of females and a very small number of males. A herd of cows with a few prize bulls or a flock of hens with one rooster are the most economical sex ratios for domesticated livestock.

See also[link]

• Bride kidnapping
• Demographic transition
• Evolution of sex
• Human sex ratio
• List of countries by sex ratio
• Operational sex ratio
• Sex allocation
• Sex selection
• Sex-selective abortion and infanticide
• Trivers–Willard hypothesis
• XY sex-determination system
• Youth bulge

Notes[link]

References[link]

• Coale A.J. (1996). "Five Decades of Missing Females in China". Proceedings of the American Philosophical Society 140 (4): 421–50. 
• Hamilton W.D. (April 1967). "Extraordinary sex ratios. A sex-ratio theory for sex linkage and inbreeding has new implications in cytogenetics and entomology". Science 156 (3774): 477–88. DOI:10.1126/science.156.3774.477. PMID 6021675. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=6021675. 
• Nishimura, K., Jahn, G.C. (1996). "Sex allocation of three solitary ectoparasitic wasp species on bean weevil larvae: sex ratio change with host quality and local mate competition". Journal of Ethology 14 (1): 27–34. DOI:10.1007/BF02350089. 
• Trivers R.L., Willard D.E. (1973). "Natural selection of parental ability to vary the sex ratio of offspring". Science 179 (4068): 90–2. DOI:10.1126/science.179.4068.90. PMID 4682135. 
• Rath, R.M., and Mishra A.K. (2005). Techniques for Sex Ratio Analysis. Association of Professional Geographers.

External links[link]

• Declining sex ratios in industrialized countries — environmental hazards
• Sex ratio in communities with high Hepatitis B favours boys^{[dead link]}
• CIA listing of sex ratios for individual countries (including age divisions)
• A review of sex ratio theory
• The Evolutionary Theory of Sex: Sex Ratio

The male gamete (sperm) fertilizing the female gamete (egg cell)

In biology, sexual reproduction is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into a male or female variety, each known as a sex. Sexual reproduction involves combining specialized cells (gametes) to form offspring that inherit traits from both parents. Gametes can be identical in form and function (known as isogametes), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist: male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism.

An organism's sex is defined by the gametes it produces: males produce male gametes (spermatozoa, or sperm) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience.

Evolution[link]

It is considered that sexual reproduction first appeared about a billion years ago, evolved within ancestral single-celled eukaryotes.^[1] The reason for the initial evolution of sex, and the reason(s) it has survived to the present, are still matters of debate. Some of the many plausible theories include: that sex creates variation among offspring, sex helps in the spread of advantageous traits, and that sex helps in the removal of disadvantageous traits.

Sexual reproduction is a process specific to eukaryotes, organisms whose cells contain a nucleus and mitochondria. In addition to animals, plants, and fungi, other eukaryotes (e.g. the malaria parasite) also engage in sexual reproduction. Some bacteria use conjugation to transfer genetic material between cells; while not the same as sexual reproduction, this also results in the mixture of genetic traits.

What is considered defining of sexual reproduction is the difference between the gametes and the binary nature of fertilization. Multiplicity of gamete types within a species would still be considered a form of sexual reproduction. However, no third gamete is known in multicellular animals.^[2][3][4]

While the evolution of sex itself dates to the eukaryote stage, the origin of chromosomal sex determination is younger. The ZW sex-determination system is shared by birds, some fish and some crustaceans. Most mammals, but also some insects (Drosophila) and plants (Ginkgo) use XY sex-determination. X0 sex-determination is found in certain insects.

No genes are shared between the avian ZW and mammal XY chromosomes,^[5] and from a comparison between chicken and human, the Z chromosome appeared similar to the autosomal chromosome 9 in human, rather than X or Y, suggesting that the ZW and XY sex-determination systems do not share an origin, but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor of birds and mammals. A paper from 2004 compared the chicken Z chromosome with platypus X chromosomes and suggested that the two systems are related.^[6]

Sexual reproduction[link]

The life cycle of sexually reproducing organisms cycles through haploid and diploid stages.

Sexual reproduction is a process where organisms form offspring that combine genetic traits from both parents. Chromosomes are passed on from one generation to the next in this process. Each cell in the offspring has half the chromosomes of the mother and half of the father.^[7] Genetic traits are contained within the deoxyribonucleic acid (DNA) of chromosomes – by combining one of each type of chromosomes from each parent, an organism is formed containing a doubled set of chromosomes. This double-chromosome stage is called "diploid", while the single-chromosome stage is "haploid". Diploid organisms can, in turn, form haploid cells (gametes) that randomly contain one of each of the chromosome pairs, via a process called meiosis.^[8] Meiosis also involves a stage of chromosomal crossover, in which regions of DNA are exchanged between matched types of chromosomes, to form a new pair of mixed chromosomes. Crossing over and fertilization (the recombining of single sets of chromosomes to make a new diploid) result in the new organism containing a different set of genetic traits from either parent.

In many organisms, the haploid stage has been reduced to just gametes specialized to recombine and form a new diploid organism; in others, the gametes are capable of undergoing cell division to produce multicellular haploid organisms. In either case, gametes may be externally similar, particularly in size (isogamy), or may have evolved an asymmetry such that the gametes are different in size and other aspects (anisogamy).^[9] By convention, the larger gamete (called an ovum, or egg cell) is considered female, while the smaller gamete (called a spermatozoon, or sperm cell) is considered male. An individual that produces exclusively large gametes is female, and one that produces exclusively small gametes is male. An individual that produces both types of gametes is a hermaphrodite; in some cases hermaphrodites are able to self-fertilize and produce offspring on their own, without a second organism.^[10]

Animals[link]

Hoverflies engaging in sexual intercourse

Most sexually reproducing animals spend their lives as diploid organisms, with the haploid stage reduced to single cell gametes.^[11] The gametes of animals have male and female forms—spermatozoa and egg cells. These gametes combine to form embryos which develop into a new organism.

The male gamete, a spermatozoon (produced within a testicle), is a small cell containing a single long flagellum which propels it.^[12] Spermatozoa are extremely reduced cells, lacking many cellular components that would be necessary for embryonic development. They are specialized for motility, seeking out an egg cell and fusing with it in a process called fertilization.

Female gametes are egg cells (produced within ovaries), large immobile cells that contain the nutrients and cellular components necessary for a developing embryo.^[13] Egg cells are often associated with other cells which support the development of the embryo, forming an egg. In mammals, the fertilized embryo instead develops within the female, receiving nutrition directly from its mother.

Animals are usually mobile and seek out a partner of the opposite sex for mating. Animals which live in the water can mate using external fertilization, where the eggs and sperm are released into and combine within the surrounding water.^[14] Most animals that live outside of water, however, must transfer sperm from male to female to achieve internal fertilization.

In most birds, both excretion and reproduction is done through a single posterior opening, called the cloaca—male and female birds touch cloaca to transfer sperm, a process called "cloacal kissing".^[15] In many other terrestrial animals, males use specialized sex organs to assist the transport of sperm—these male sex organs are called intromittent organs. In humans and other mammals this male organ is the penis, which enters the female reproductive tract (called the vagina) to achieve insemination—a process called sexual intercourse. The penis contains a tube through which semen (a fluid containing sperm) travels. In female mammals the vagina connects with the uterus, an organ which directly supports the development of a fertilized embryo within (a process called gestation).

Because of their motility, animal sexual behavior can involve coercive sex. Traumatic insemination, for example, is used by some insect species to inseminate females through a wound in the abdominal cavity – a process detrimental to the female's health.

Plants[link]

Flowers are the sexual organs of flowering plants, usually containing both male and female parts.

Like animals, plants have developed specialized male and female gametes.^[16] Within most familiar plants, male gametes are contained within hard coats, forming pollen. The female gametes of plants are contained within ovules; once fertilized by pollen these form seeds which, like eggs, contain the nutrients necessary for the development of the embryonic plant.

Female (left) and male (right) cones are the sex organs of pines and other conifers.

Many plants have flowers and these are the sexual organs of those plants. Flowers are usually hermaphroditic, producing both male and female gametes. The female parts, in the center of a flower, are the carpels—one or more of these may be merged to form a single pistil. Within carpels are ovules which develop into seeds after fertilization. The male parts of the flower are the stamens: these long filamentous organs are arranged between the pistil and the petals and produce pollen at their tips. When a pollen grain lands upon the top of a carpel, the tissues of the plant react to transport the grain down into the carpel to merge with an ovule, eventually forming seeds.

In pines and other conifers the sex organs are conifer cones and have male and female forms. The more familiar female cones are typically more durable, containing ovules within them. Male cones are smaller and produce pollen which is transported by wind to land in female cones. As with flowers, seeds form within the female cone after pollination.

Because plants are immobile, they depend upon passive methods for transporting pollen grains to other plants. Many plants, including conifers and grasses, produce lightweight pollen which is carried by wind to neighboring plants. Other plants have heavier, sticky pollen that is specialized for transportation by insects. The plants attract these insects with nectar-containing flowers. Insects transport the pollen as they move to other flowers, which also contain female reproductive organs, resulting in pollination.

Fungi[link]

Mushrooms are produced as part of fungal sexual reproduction

Most fungi reproduce sexually, having both a haploid and diploid stage in their life cycles. These fungi are typically isogamous, lacking male and female specialization: haploid fungi grow into contact with each other and then fuse their cells. In some of these cases the fusion is asymmetric, and the cell which donates only a nucleus (and not accompanying cellular material) could arguably be considered "male".^[17]

Some fungi, including baker's yeast, have mating types that create a duality similar to male and female roles. Yeast with the same mating type will not fuse with each other to form diploid cells, only with yeast carrying the other mating type.^[18]

Fungi produce mushrooms as part of their sexual reproduction. Within the mushroom diploid cells are formed, later dividing into haploid spores—the height of the mushroom aids the dispersal of these sexually produced offspring.

Sex helps the spread of advantageous traits through recombination. The diagrams compare evolution of allele frequency in a sexual population (top) and an asexual population (bottom). The vertical axis shows frequency and the horizontal axis shows time. The alleles a/A and b/B occur at random. The advantageous alleles A and B, arising independently, can be rapidly combined by sexual reproduction into the most advantageous combination AB. Asexual reproduction takes longer to achieve this combination, because it can only produce AB if A arises in an individual which already has B, or vice versa.

Sex determination[link]

The most basic sexual system is one in which all organisms are hermaphrodites, producing both male and female gametes—this is true of some animals (e.g. snails) and the majority of flowering plants.^[19] In many cases, however, specialization of sex has evolved such that some organisms produce only male or only female gametes. The biological cause for an organism developing into one sex or the other is called sex determination.

In the majority of species with sex specialization, organisms are either male (producing only male gametes) or female (producing only female gametes). Exceptions are common—for example, in the roundworm C. elegans the two sexes are hermaphrodite and male (a system called androdioecy).

Sometimes an organism's development is intermediate between male and female, a condition called intersex. Sometimes intersex individuals are called "hermaphrodite"; but, unlike biological hermaphrodites, intersex individuals are unusual cases and are not typically fertile in both male and female aspects.

Genetic[link]

Like humans and other mammals, the common fruit fly has an XY sex-determination system.

In genetic sex-determination systems, an organism's sex is determined by the genome it inherits. Genetic sex-determination usually depends on asymmetrically inherited sex chromosomes which carry genetic features that influence development; sex may be determined either by the presence of a sex chromosome or by how many the organism has. Genetic sex-determination, because it is determined by chromosome assortment, usually results in a 1:1 ratio of male and female offspring.

Humans and other mammals have an XY sex-determination system: the Y chromosome carries factors responsible for triggering male development. The default sex, in the absence of a Y chromosome, is female. Thus, XX mammals are female and XY are male. XY sex determination is found in other organisms, including the common fruit fly and some plants.^[19] In some cases, including in the fruit fly, it is the number of X chromosomes that determines sex rather than the presence of a Y chromosome (see below).

In birds, which have a ZW sex-determination system, the opposite is true: the W chromosome carries factors responsible for female development, and default development is male.^[20] In this case ZZ individuals are male and ZW are female. The majority of butterflies and moths also have a ZW sex-determination system. In both XY and ZW sex determination systems, the sex chromosome carrying the critical factors is often significantly smaller, carrying little more than the genes necessary for triggering the development of a given sex.^[21]

Many insects use a sex determination system based on the number of sex chromosomes. This is called X0 sex-determination—the 0 indicates the absence of the sex chromosome. All other chromosomes in these organisms are diploid, but organisms may inherit one or two X chromosomes. In field crickets, for example, insects with a single X chromosome develop as male, while those with two develop as female.^[22] In the nematode C. elegans most worms are self-fertilizing XX hermaphrodites, but occasionally abnormalities in chromosome inheritance regularly give rise to individuals with only one X chromosome—these X0 individuals are fertile males (and half their offspring are male).^[23]

Other insects, including honey bees and ants, use a haplodiploid sex-determination system.^[24] In this case diploid individuals are generally female, and haploid individuals (which develop from unfertilized eggs) are male. This sex-determination system results in highly biased sex ratios, as the sex of offspring is determined by fertilization rather than the assortment of chromosomes during meiosis.

Clownfish are initially male; the largest fish in a group becomes female.

Nongenetic[link]

For many species sex is not determined by inherited traits, but instead by environmental factors experienced during development or later in life. Many reptiles have temperature-dependent sex determination: the temperature embryos experience during their development determines the sex of the organism. In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1–2°C.

Many fish change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism. In clownfish, smaller fish are male, and the dominant and largest fish in a group becomes female. In many wrasses the opposite is true—most fish are initially female and become male when they reach a certain size. Sequential hermaphrodites may produce both types of gametes over the course of their lifetime, but at any given point they are either female or male.

In some ferns the default sex is hermaphrodite, but ferns which grow in soil that has previously supported hermaphrodites are influenced by residual hormones to instead develop as male.^[25]

Sexual dimorphism[link]

Common Pheasants are sexually dimorphic in both size and appearance.

Many animals have differences between the male and female sexes in size and appearance, a phenomenon called sexual dimorphism. Sexual dimorphisms are often associated with sexual selection – the competition between individuals of one sex to mate with the opposite sex.^[26] Antlers in male deer, for example, are used in combat between males to win reproductive access to female deer. In many cases the male of a species is larger in size; in mammals species with high sexual size dimorphism tend to have highly polygynous mating systems—presumably due to selection for success in competition with other males.

Other animals, including most insects and many fish, have larger females. This may be associated with the cost of producing egg cells, which requires more nutrition than producing sperm—larger females are able to produce more eggs.^[27] Occasionally this dimorphism is extreme, with males reduced to living as parasites dependent on the female.

In birds, males often have a more colourful appearance and may have features (like the long tail of male peacocks) that would seem to put the organism at a disadvantage (e.g. bright colors would seem to make a bird more visible to predators). One proposed explanation for this is the handicap principle.^[28] This hypothesis says that, by demonstrating he can survive with such handicaps, the male is advertising his genetic fitness to females—traits that will benefit daughters as well, who will not be encumbered with such handicaps.

Sex differences in humans include, generally, a larger size and more body hair in men; women have breasts, wider hips, and a higher body fat percentage.

References[link]

Further reading[link]

External links[link]

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	Book: Sex
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• Human Sexual Differentiation by P. C. Sizonenko
• New Scientist article on Sex chromosomes in the platypus

Narinder Singh Kapany
Born	Moga, Punjab, British India
Residence	United States
Nationality	United States
Fields	Physics
Institutions	Agra University Ordnance Factories Organisation Imperial College of Science British Royal Academy of Engineering Optical Society of America American Association for the Advancement of Science Professor at the University of California, Berkeley (UCB) University of California, Santa Cruz (UCSC) Stanford University
Alma mater	Agra University Imperial College London
Known for	Invention of Fiber optics (The father of fibre optics).
Notable awards	Pravasi Bharatiya Samman The Excellence 2000 Award.

Narinder Singh Kapany Punjabi: ਨਰਿੰਦਰ ਸਿੰਘ (born 12 October 1926 in Moga, Punjab) is an Indian born American physicist known for his work in fiber optics.^{[1][2][3][4][5]} He was named as one of the seven 'Unsung Heroes' by Fortune magazine in their ‘Businessmen of the Century’ issue (1999-11-22).^[2][3][5]

Early life[link]

Narinder Singh was born in Moga, Punjab, India and educated in India and England, Kapany has lived in the United States for forty-five years. In 1952, this earlier work led Kapany to conduct studies that led to the invention of optical fiber. A graduate of Agra University in India, he completed advanced studies in optics, and Ph.D. degree at Imperial College London in 1955.

His career has spanned science, entrepreneurship and management, academia, publishing, lecturing, and farming. His personal interests include philanthropy, art collecting, and sculpting.

Kapany is considered as one of the founders of fiber optics.^{[1][2] [3][4]} His research and inventions have encompassed fiber-optics communications, lasers, biomedical instrumentation, solar energy and pollution monitoring. He has over one hundred patents, and was a member of the National Inventors Council. He has received many awards including 'The Excellence 2000 Award' from the USA Pan-Asian American Chamber of Commerce in 1998. He is a Fellow of numerous scientific societies including the British Royal Academy of Engineering, the Optical Society of America, and the American Association for the Advancement of Science.

Kapany lives in the Bay Area with his wife, Satinder. His son, Rajinder, is a hi-tech executive; and his daughter, Kiren, is an attorney and filmmaker.

Businessman & entrepreneur[link]

Optical fibers

As an entrepreneur and business executive, Kapany has specialized in the processes of innovation and the management of technology and technology transfer. In 1960, he founded Optics Technology Inc. and was Chairman of the Board, President, and Director of Research for twelve years. In 1967 the company went public with numerous corporate acquisitions and joint-ventures in the United States and abroad. In 1973, Kapany founded Kaptron Inc. and was President and CEO until 1990 when he sold the company to AMP Incorporated. For the next nine years, Kapany was an AMP Fellow, heading the Intrapreneur & Technical Expert Program and serving as Chief Technologist for Global Communications Business. He recently founded K2 Optronics. He has also served on the boards of various companies. He was a member of the Young Presidents Organization and is presently a member of the World Presidents Organization.

As an academic, Kapany has taught and supervised research activity of postgraduate students. He was a Regents Professor at the University of California, Berkeley (UCB), and at the University of California, Santa Cruz (UCSC). He was also Director of the Center for Innovation and Entrepreneurial Development (CIED) at UCSC for seven years. At Stanford University, he was a Visiting Scholar in the Physics Department and Consulting Professor in the Department of Electrical Engineering.

Research scholar[link]

As an author and lecturer, Kapany has published over 100 scientific papers and four books on opto-electronics and entrepreneurship. He has lectured to various national and international scientific societies. His popular article on Fibre optics in Scientific American in 1960 established the new term (Fibre optics); the article constitutes a reference point for the subject even today. In November 1999, Fortune magazine published profiles of seven people who have greatly influenced life in the twentieth century but are unsung heroes. Kapany was one of them.^[5]

Philanthropist[link]

As a philanthropist, Kapany has been active in education and the arts. He has been the founding chairman and major funder of the Sikh Foundation and its activities for over 30 years.^[6] In collaboration with international institutions and publishers, the Foundation runs programs in publishing, academia and the arts. In 1998, Kapany endowed a Chair of Sikh Studies at the University of California, Santa Barbara. His gift in 1999 of $500,000 to the Asian Art Museum of San Francisco will establish a gallery in its new building displaying the works he has donated from his collection of Sikh art. In 1999, he endowed a Chair of Opto-Electronics at the University of California, Santa Cruz. He is also trustee of the University of California, Santa Cruz Foundation. He has served as a trustee of the Menlo School in Menlo Park, California.

As an art collector, Kapany has specialized in Sikh art. He provided paintings and other objects on loan for the internationally acclaimed 'Arts of the Sikh Kingdoms' exhibition, which was held at London's Victoria & Albert Museum beginning in March 1999; from there, the exhibition proceeded to the Asian Art Museum of San Francisco (with the Sikh Foundation as a sponsor) and opened in May 2000 at the Royal Ontario Museum in Toronto. The exhibition follows 'Splendors of the Punjab: Sikh Art and Literature in 1992' organized by Kapany in collaboration with the Asian Art Museum and UC Berkeley to celebrate the 25th anniversary of the Sikh Foundation.

As an artist, Kapany has created 40 "dynoptic" sculptures which were first displayed in a one-man show at the Exploratorium of the Palace of Fine Arts in San Francisco in 1972. Since then, the collection has been viewed at museums and art galleries in Chicago, Monterey, Palo Alto, and Stanford.

References[link]

External links[link]

• Article on Dr. Narinder Singh Kapany
• News Article on Narinder Singh Kapany